Refractory panel sheet



Patented Apr. 2, 1940 I t Y 2,195,881

UNITED STATES PATENT, OFFICE REFRACTORY PANEL SHEET Clements Batcheller,Glens Falls, N. Y., assignor to Allegheny Ludlum Steel Corporation,Pittsburgh, Pa., a corporation of Pennsylvania No Drawing; ApplicationMay 21; 1937,

. Serial No. 144,031

3 Claims. (Cl. 106 24) My invention relates to refractory panels, andstand an applied temperature up to about 2000 particularly to panelswhich, although they are F. Without superficial crazing or spalling and,hard and have comparatively high structural what is most important,without reducing the strength, are nevertheless of low specific gravity,structural integrity of the product to a point 5 whereby they areparticularly adapted for use in Where failure is indicated. Similarproducts 5 connection with the interior construction of made by anymechanical procedure when comships, railroad cars, aircraft, and thelike, where posed principally of Portland cement and mineral low weightis absolutely necessary. Another obfibers become utterly useless attemperatures of -ject of my invention is to provide a product of theorder of about 1500 F. The ordinary cementthis kind in which wasteasbestos fibers of a asbestos products, for example, when subjected to10 grade heretofore considered unsuitable for use in temperatures of theorder of about 1000 F. and

standard types of cement-asbestos hard-pressed over break down rapidly.This is due in part to sheets may be employed and particularly to a thecalcination of the asbestos fibers and the repanel board or sheet whichcan be produced on lease of chemical water which causes the prodacylinder press. ucts to explode under such conditions. 16

Many grades of asbestos fibers while entirely For some unexplainedreason my products satisfactory in the matter of tensile strength, etc.,when formed from waste asbestos fibers containcannot be used in themanufacture of sheet proding appreciable quantities of talc are somewhatucts of the character contemplated hereunder stronger and better thanthe same products 20 when formed upon a cylinder press by reason offormed from the highest grade of asbestos fibers go the presence of talcwhich retards or even entire such as those obtained from the areas ofeastern lyprevents the successful removal of the felted Quebec, Canadaalthough it is to be understood plastic sheet from the cylinder drum ofthe mathat my invention, of course, is not limited to they chine, due toexcessive sticking. use of such waste fibers.

I have discovered that it is possible to produce My products when formedto an appreciable 35 my products to high degrees of strength fromexthickness, say f to 1" produce extremely eftremely low grade asbestosfibers and that the ,ficient'structurel barriers st e passa e ofpresence therein of talc in any reasonable high heat. I quantity has nodetrimental effect upon either The proportions of the ingredients givenin the machine formation of the product or its the above formula may, ofcourse, be varied to 30 ultimate strength and quality. some degree, butthe following limitations should By forming my products largely fromcalcined be observed. The diatomaceous earth should be diatomaceousearth, which weighs only from 10 maintained substantially in excess ofany other to 16 pounds per cubic foot, not only is a very ingredient andthe diatomaceous earth and light product produced but one which iscapable bentonite combined should constitute 50% or 35 of withstandingextremely high temperatures 0 y Weight, of the composition n O der towithout disintegrating. The diatomaceous earth provide a product of lowspecific gravity commay be either granular or finely ground, and a binedwith resistance to high heat. Increasing typical formula which I havefound highly t the magnesite content andreducing the Portland 40 factoryisas follows: cement content will enhance the structural 4o t-, strengthof the product, and vice versa, while the Portland cement 300 bentonitecontent, due to the fact that it excalcined di t ma arth 700 pands, whenwet, to as much as fourteen times its Calcined magnesite t 200 originalvolume, preferably does not exceed about Bentonite clay (200 mesh) 150 yW t, o the composition. However, 45 Waste asbestos fibers (either t orthe total cement content, that is the Portland it t t as an aduuerant)250 3u0 cement and magnesite content combined, should Water to produce aworkable consistency. be at least by Weight, although ore than 35% willprobably not be desirable in any case. The procedure followed in makingmy products What I claim r the above formula is Substantmny the Well 1.A refractory panel sheet characterized by its known Hatschek processwhich employs a Wet comparatively low specific gravity'and its highcylinder press and is widely used in the formaresistance to crazing,spalling and structural distion of cement-asbestos products. Sheets orintegration under applied heat up to temperapanels made from the aboveformula will withtures of the order of about 2000 F., said sheet acontaining, by weight, the following ingredients, in about theproportions stated Parts Portland cement 300 Diatomaceous earth 700Magnesium hydrate 200 Bentonite 150 Asbestos fibers 250-300 50% or moreby weight of the sheet; the combined weight of the Portland cement andmagnesium hydrate contents constituting from about to of the weight ofthe product, and the balance being principally asbestos fibers.

3. A refractory panel sheet characterized by its comparatively lowspecific gravity and its high resistance to crazing, spalling andstructural disintegration under applied heat up to temperatures of theorder of about 2000 F., and containing diatomaceous earth, asbestosfibers, Portland cement, magnesium hydrate and bentonite; thediatomaceous earth content constituting at least of the total weight ofthe sheet, the Portland cement and magnesium hydrate contents combinedconstituting at least 25% of said total weight, and the balance beingsubstantially bentonite and asbestos fibers.

CLEMENTS BATCHELLE'R.

